﻿//
// Options.cs
//
// Authors:
//  Jonathan Pryor <jpryor@novell.com>
//  Federico Di Gregorio <fog@initd.org>
//
// Copyright (C) 2008 Novell (http://www.novell.com)
// Copyright (C) 2009 Federico Di Gregorio.
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

// Compile With:
//   gmcs -debug+ -r:System.Core Options.cs -o:NDesk.Options.dll
//   gmcs -debug+ -d:LINQ -r:System.Core Options.cs -o:NDesk.Options.dll
//
// The LINQ version just changes the implementation of
// OptionSet.Parse(IEnumerable<string>), and confers no semantic changes.

//
// A Getopt::Long-inspired option parsing library for C#.
//
// NDesk.Options.OptionSet is built upon a key/value table, where the
// key is a option format string and the value is a delegate that is 
// invoked when the format string is matched.
//
// Option format strings:
//  Regex-like BNF Grammar: 
//    name: .+
//    type: [=:]
//    sep: ( [^{}]+ | '{' .+ '}' )?
//    aliases: ( name type sep ) ( '|' name type sep )*
// 
// Each '|'-delimited name is an alias for the associated action.  If the
// format string ends in a '=', it has a required value.  If the format
// string ends in a ':', it has an optional value.  If neither '=' or ':'
// is present, no value is supported.  `=' or `:' need only be defined on one
// alias, but if they are provided on more than one they must be consistent.
//
// Each alias portion may also end with a "key/value separator", which is used
// to split option values if the option accepts > 1 value.  If not specified,
// it defaults to '=' and ':'.  If specified, it can be any character except
// '{' and '}' OR the *string* between '{' and '}'.  If no separator should be
// used (i.e. the separate values should be distinct arguments), then "{}"
// should be used as the separator.
//
// Options are extracted either from the current option by looking for
// the option name followed by an '=' or ':', or is taken from the
// following option IFF:
//  - The current option does not contain a '=' or a ':'
//  - The current option requires a value (i.e. not a Option type of ':')
//
// The `name' used in the option format string does NOT include any leading
// option indicator, such as '-', '--', or '/'.  All three of these are
// permitted/required on any named option.
//
// Option bundling is permitted so long as:
//   - '-' is used to start the option group
//   - all of the bundled options are a single character
//   - at most one of the bundled options accepts a value, and the value
//     provided starts from the next character to the end of the string.
//
// This allows specifying '-a -b -c' as '-abc', and specifying '-D name=value'
// as '-Dname=value'.
//
// Option processing is disabled by specifying "--".  All options after "--"
// are returned by OptionSet.Parse() unchanged and unprocessed.
//
// Unprocessed options are returned from OptionSet.Parse().
//
// Examples:
//  int verbose = 0;
//  OptionSet p = new OptionSet ()
//    .Add ("v", v => ++verbose)
//    .Add ("name=|value=", v => Console.WriteLine (v));
//  p.Parse (new string[]{"-v", "--v", "/v", "-name=A", "/name", "B", "extra"});
//
// The above would parse the argument string array, and would invoke the
// lambda expression three times, setting `verbose' to 3 when complete.  
// It would also print out "A" and "B" to standard output.
// The returned array would contain the string "extra".
//
// C# 3.0 collection initializers are supported and encouraged:
//  var p = new OptionSet () {
//    { "h|?|help", v => ShowHelp () },
//  };
//
// System.ComponentModel.TypeConverter is also supported, allowing the use of
// custom data types in the callback type; TypeConverter.ConvertFromString()
// is used to convert the value option to an instance of the specified
// type:
//
//  var p = new OptionSet () {
//    { "foo=", (Foo f) => Console.WriteLine (f.ToString ()) },
//  };
//
// Random other tidbits:
//  - Boolean options (those w/o '=' or ':' in the option format string)
//    are explicitly enabled if they are followed with '+', and explicitly
//    disabled if they are followed with '-':
//      string a = null;
//      var p = new OptionSet () {
//        { "a", s => a = s },
//      };
//      p.Parse (new string[]{"-a"});   // sets v != null
//      p.Parse (new string[]{"-a+"});  // sets v != null
//      p.Parse (new string[]{"-a-"});  // sets v == null
//

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Globalization;
using System.IO;
using System.Runtime.Serialization;
using System.Security.Permissions;
using System.Text;
using System.Text.RegularExpressions;

#if LINQ
using System.Linq;
#endif

#if TEST
using NDesk.Options;
#endif

#if NDESK_OPTIONS
namespace NDesk.Options
#else
namespace Mono.Options
#endif
{
	static class StringCoda
	{

		public static IEnumerable<string> WrappedLines( string self, params int[] widths )
		{
			IEnumerable<int> w = widths;
			return WrappedLines( self, w );
		}

		public static IEnumerable<string> WrappedLines( string self, IEnumerable<int> widths )
		{
			if( widths == null )
				throw new ArgumentNullException( "widths" );
			return CreateWrappedLinesIterator( self, widths );
		}

		private static IEnumerable<string> CreateWrappedLinesIterator( string self, IEnumerable<int> widths )
		{
			if( string.IsNullOrEmpty( self ) )
			{
				yield return string.Empty;
				yield break;
			}
			using( IEnumerator<int> ewidths = widths.GetEnumerator() )
			{
				bool? hw = null;
				int width = GetNextWidth( ewidths, int.MaxValue, ref hw );
				int start = 0, end;
				do
				{
					end = GetLineEnd( start, width, self );
					char c = self[end - 1];
					if( char.IsWhiteSpace( c ) )
						--end;
					bool needContinuation = end != self.Length && !IsEolChar( c );
					string continuation = "";
					if( needContinuation )
					{
						--end;
						continuation = "-";
					}
					string line = self.Substring( start, end - start ) + continuation;
					yield return line;
					start = end;
					if( char.IsWhiteSpace( c ) )
						++start;
					width = GetNextWidth( ewidths, width, ref hw );
				} while( start < self.Length );
			}
		}

		private static int GetNextWidth( IEnumerator<int> ewidths, int curWidth, ref bool? eValid )
		{
			if( !eValid.HasValue || ( eValid.HasValue && eValid.Value ) )
			{
				curWidth = ( eValid = ewidths.MoveNext() ).Value ? ewidths.Current : curWidth;
				// '.' is any character, - is for a continuation
				const string minWidth = ".-";
				if( curWidth < minWidth.Length )
					throw new ArgumentOutOfRangeException( "widths",
							string.Format( "Element must be >= {0}, was {1}.", minWidth.Length, curWidth ) );
				return curWidth;
			}
			// no more elements, use the last element.
			return curWidth;
		}

		private static bool IsEolChar( char c )
		{
			return !char.IsLetterOrDigit( c );
		}

		private static int GetLineEnd( int start, int length, string description )
		{
			int end = System.Math.Min( start + length, description.Length );
			int sep = -1;
			for( int i = start; i < end; ++i )
			{
				if( description[i] == '\n' )
					return i + 1;
				if( IsEolChar( description[i] ) )
					sep = i + 1;
			}
			if( sep == -1 || end == description.Length )
				return end;
			return sep;
		}
	}

	public class OptionValueCollection: IList, IList<string>
	{

		List<string> values = new List<string>();
		OptionContext c;

		internal OptionValueCollection( OptionContext c )
		{
			this.c = c;
		}

		#region ICollection
		void ICollection.CopyTo( Array array, int index ) { ( values as ICollection ).CopyTo( array, index ); }
		bool ICollection.IsSynchronized { get { return ( values as ICollection ).IsSynchronized; } }
		object ICollection.SyncRoot { get { return ( values as ICollection ).SyncRoot; } }
		#endregion

		#region ICollection<T>
		public void Add( string item ) { values.Add( item ); }
		public void Clear() { values.Clear(); }
		public bool Contains( string item ) { return values.Contains( item ); }
		public void CopyTo( string[] array, int arrayIndex ) { values.CopyTo( array, arrayIndex ); }
		public bool Remove( string item ) { return values.Remove( item ); }
		public int Count { get { return values.Count; } }
		public bool IsReadOnly { get { return false; } }
		#endregion

		#region IEnumerable
		IEnumerator IEnumerable.GetEnumerator() { return values.GetEnumerator(); }
		#endregion

		#region IEnumerable<T>
		public IEnumerator<string> GetEnumerator() { return values.GetEnumerator(); }
		#endregion

		#region IList
		int IList.Add( object value ) { return ( values as IList ).Add( value ); }
		bool IList.Contains( object value ) { return ( values as IList ).Contains( value ); }
		int IList.IndexOf( object value ) { return ( values as IList ).IndexOf( value ); }
		void IList.Insert( int index, object value ) { ( values as IList ).Insert( index, value ); }
		void IList.Remove( object value ) { ( values as IList ).Remove( value ); }
		void IList.RemoveAt( int index ) { ( values as IList ).RemoveAt( index ); }
		bool IList.IsFixedSize { get { return false; } }
		object IList.this[int index] { get { return this[index]; } set { ( values as IList )[index] = value; } }
		#endregion

		#region IList<T>
		public int IndexOf( string item ) { return values.IndexOf( item ); }
		public void Insert( int index, string item ) { values.Insert( index, item ); }
		public void RemoveAt( int index ) { values.RemoveAt( index ); }

		private void AssertValid( int index )
		{
			if( c.Option == null )
				throw new InvalidOperationException( "OptionContext.Option is null." );
			if( index >= c.Option.MaxValueCount )
				throw new ArgumentOutOfRangeException( "index" );
			if( c.Option.OptionValueType == OptionValueType.Required &&
					index >= values.Count )
				throw new OptionException( string.Format(
							c.OptionSet.MessageLocalizer( "Missing required value for option '{0}'." ), c.OptionName ),
						c.OptionName );
		}

		public string this[int index]
		{
			get
			{
				AssertValid( index );
				return index >= values.Count ? null : values[index];
			}
			set
			{
				values[index] = value;
			}
		}
		#endregion

		public List<string> ToList()
		{
			return new List<string>( values );
		}

		public string[] ToArray()
		{
			return values.ToArray();
		}

		public override string ToString()
		{
			return string.Join( ", ", values.ToArray() );
		}
	}

	public class OptionContext
	{
		private Option option;
		private string name;
		private int index;
		private OptionSet set;
		private OptionValueCollection c;

		public OptionContext( OptionSet set )
		{
			this.set = set;
			this.c = new OptionValueCollection( this );
		}

		public Option Option
		{
			get { return option; }
			set { option = value; }
		}

		public string OptionName
		{
			get { return name; }
			set { name = value; }
		}

		public int OptionIndex
		{
			get { return index; }
			set { index = value; }
		}

		public OptionSet OptionSet
		{
			get { return set; }
		}

		public OptionValueCollection OptionValues
		{
			get { return c; }
		}
	}

	public enum OptionValueType
	{
		None,
		Optional,
		Required,
	}

	public abstract class Option
	{
		string prototype, description;
		string[] names;
		OptionValueType type;
		int count;
		string[] separators;

		protected Option( string prototype, string description )
			: this( prototype, description, 1 )
		{
		}

		protected Option( string prototype, string description, int maxValueCount )
		{
			if( prototype == null )
				throw new ArgumentNullException( "prototype" );
			if( prototype.Length == 0 )
				throw new ArgumentException( "Cannot be the empty string.", "prototype" );
			if( maxValueCount < 0 )
				throw new ArgumentOutOfRangeException( "maxValueCount" );

			this.prototype = prototype;
			this.description = description;
			this.count = maxValueCount;
			this.names = ( this is OptionSet.Category )
				// append GetHashCode() so that "duplicate" categories have distinct
				// names, e.g. adding multiple "" categories should be valid.
				? new[] { prototype + this.GetHashCode() }
				: prototype.Split( '|' );

			if( this is OptionSet.Category )
				return;

			this.type = ParsePrototype();

			if( this.count == 0 && type != OptionValueType.None )
				throw new ArgumentException(
						"Cannot provide maxValueCount of 0 for OptionValueType.Required or " +
							"OptionValueType.Optional.",
						"maxValueCount" );
			if( this.type == OptionValueType.None && maxValueCount > 1 )
				throw new ArgumentException(
						string.Format( "Cannot provide maxValueCount of {0} for OptionValueType.None.", maxValueCount ),
						"maxValueCount" );
			if( Array.IndexOf( names, "<>" ) >= 0 &&
					( ( names.Length == 1 && this.type != OptionValueType.None ) ||
					 ( names.Length > 1 && this.MaxValueCount > 1 ) ) )
				throw new ArgumentException(
						"The default option handler '<>' cannot require values.",
						"prototype" );
		}

		public string Prototype { get { return prototype; } }
		public string Description { get { return description; } }
		public OptionValueType OptionValueType { get { return type; } }
		public int MaxValueCount { get { return count; } }

		public string[] GetNames()
		{
			return (string[])names.Clone();
		}

		public string[] GetValueSeparators()
		{
			if( separators == null )
				return new string[0];
			return (string[])separators.Clone();
		}

		protected static T Parse<T>( string value, OptionContext c )
		{
			Type tt = typeof( T );
			bool nullable = tt.IsValueType && tt.IsGenericType &&
				!tt.IsGenericTypeDefinition &&
				tt.GetGenericTypeDefinition() == typeof( Nullable<> );
			Type targetType = nullable ? tt.GetGenericArguments()[0] : typeof( T );
			TypeConverter conv = TypeDescriptor.GetConverter( targetType );
			T t = default( T );
			try
			{
				if( value != null )
					t = (T)conv.ConvertFromString( value );
			}
			catch( Exception e )
			{
				throw new OptionException(
						string.Format(
							c.OptionSet.MessageLocalizer( "Could not convert string `{0}' to type {1} for option `{2}'." ),
							value, targetType.Name, c.OptionName ),
						c.OptionName, e );
			}
			return t;
		}

		internal string[] Names { get { return names; } }
		internal string[] ValueSeparators { get { return separators; } }

		static readonly char[] NameTerminator = new char[] { '=', ':' };

		private OptionValueType ParsePrototype()
		{
			char type = '\0';
			List<string> seps = new List<string>();
			for( int i = 0; i < names.Length; ++i )
			{
				string name = names[i];
				if( name.Length == 0 )
					throw new ArgumentException( "Empty option names are not supported.", "prototype" );

				int end = name.IndexOfAny( NameTerminator );
				if( end == -1 )
					continue;
				names[i] = name.Substring( 0, end );
				if( type == '\0' || type == name[end] )
					type = name[end];
				else
					throw new ArgumentException(
							string.Format( "Conflicting option types: '{0}' vs. '{1}'.", type, name[end] ),
							"prototype" );
				AddSeparators( name, end, seps );
			}

			if( type == '\0' )
				return OptionValueType.None;

			if( count <= 1 && seps.Count != 0 )
				throw new ArgumentException(
						string.Format( "Cannot provide key/value separators for Options taking {0} value(s).", count ),
						"prototype" );
			if( count > 1 )
			{
				if( seps.Count == 0 )
					this.separators = new string[] { ":", "=" };
				else if( seps.Count == 1 && seps[0].Length == 0 )
					this.separators = null;
				else
					this.separators = seps.ToArray();
			}

			return type == '=' ? OptionValueType.Required : OptionValueType.Optional;
		}

		private static void AddSeparators( string name, int end, ICollection<string> seps )
		{
			int start = -1;
			for( int i = end + 1; i < name.Length; ++i )
			{
				switch( name[i] )
				{
				case '{':
					if( start != -1 )
						throw new ArgumentException(
								string.Format( "Ill-formed name/value separator found in \"{0}\".", name ),
								"prototype" );
					start = i + 1;
					break;
				case '}':
					if( start == -1 )
						throw new ArgumentException(
								string.Format( "Ill-formed name/value separator found in \"{0}\".", name ),
								"prototype" );
					seps.Add( name.Substring( start, i - start ) );
					start = -1;
					break;
				default:
					if( start == -1 )
						seps.Add( name[i].ToString() );
					break;
				}
			}
			if( start != -1 )
				throw new ArgumentException(
						string.Format( "Ill-formed name/value separator found in \"{0}\".", name ),
						"prototype" );
		}

		public void Invoke( OptionContext c )
		{
			OnParseComplete( c );
			c.OptionName = null;
			c.Option = null;
			c.OptionValues.Clear();
		}

		protected abstract void OnParseComplete( OptionContext c );

		public override string ToString()
		{
			return Prototype;
		}
	}

	public abstract class ArgumentSource
	{

		protected ArgumentSource()
		{
		}

		public abstract string[] GetNames();
		public abstract string Description { get; }
		public abstract bool GetArguments( string value, out IEnumerable<string> replacement );

		public static IEnumerable<string> GetArgumentsFromFile( string file )
		{
			return GetArguments( File.OpenText( file ), true );
		}

		public static IEnumerable<string> GetArguments( TextReader reader )
		{
			return GetArguments( reader, false );
		}

		// Cribbed from mcs/driver.cs:LoadArgs(string)
		static IEnumerable<string> GetArguments( TextReader reader, bool close )
		{
			try
			{
				StringBuilder arg = new StringBuilder();

				string line;
				while( ( line = reader.ReadLine() ) != null )
				{
					int t = line.Length;

					for( int i = 0; i < t; i++ )
					{
						char c = line[i];

						if( c == '"' || c == '\'' )
						{
							char end = c;

							for( i++; i < t; i++ )
							{
								c = line[i];

								if( c == end )
									break;
								arg.Append( c );
							}
						}
						else if( c == ' ' )
						{
							if( arg.Length > 0 )
							{
								yield return arg.ToString();
								arg.Length = 0;
							}
						}
						else
							arg.Append( c );
					}
					if( arg.Length > 0 )
					{
						yield return arg.ToString();
						arg.Length = 0;
					}
				}
			}
			finally
			{
				if( close )
					reader.Close();
			}
		}
	}

	public class ResponseFileSource: ArgumentSource
	{

		public override string[] GetNames()
		{
			return new string[] { "@file" };
		}

		public override string Description
		{
			get { return "Read response file for more options."; }
		}

		public override bool GetArguments( string value, out IEnumerable<string> replacement )
		{
			if( string.IsNullOrEmpty( value ) || !value.StartsWith( "@" ) )
			{
				replacement = null;
				return false;
			}
			replacement = ArgumentSource.GetArgumentsFromFile( value.Substring( 1 ) );
			return true;
		}
	}

	[Serializable]
	public class OptionException: Exception
	{
		private string option;

		public OptionException()
		{
		}

		public OptionException( string message, string optionName )
			: base( message )
		{
			this.option = optionName;
		}

		public OptionException( string message, string optionName, Exception innerException )
			: base( message, innerException )
		{
			this.option = optionName;
		}

		protected OptionException( SerializationInfo info, StreamingContext context )
			: base( info, context )
		{
			this.option = info.GetString( "OptionName" );
		}

		public string OptionName
		{
			get { return this.option; }
		}

		[SecurityPermission( SecurityAction.LinkDemand, SerializationFormatter = true )]
		public override void GetObjectData( SerializationInfo info, StreamingContext context )
		{
			base.GetObjectData( info, context );
			info.AddValue( "OptionName", option );
		}
	}

	public delegate void OptionAction<TKey, TValue>( TKey key, TValue value );

	public class OptionSet: KeyedCollection<string, Option>
	{
		public OptionSet()
			: this( delegate( string f ) { return f; } )
		{
		}

		public OptionSet( Converter<string, string> localizer )
		{
			this.localizer = localizer;
			this.roSources = new ReadOnlyCollection<ArgumentSource>( sources );
		}

		Converter<string, string> localizer;

		public Converter<string, string> MessageLocalizer
		{
			get { return localizer; }
		}

		List<ArgumentSource> sources = new List<ArgumentSource>();
		ReadOnlyCollection<ArgumentSource> roSources;

		public ReadOnlyCollection<ArgumentSource> ArgumentSources
		{
			get { return roSources; }
		}


		protected override string GetKeyForItem( Option item )
		{
			if( item == null )
				throw new ArgumentNullException( "option" );
			if( item.Names != null && item.Names.Length > 0 )
				return item.Names[0];
			// This should never happen, as it's invalid for Option to be
			// constructed w/o any names.
			throw new InvalidOperationException( "Option has no names!" );
		}

		[Obsolete( "Use KeyedCollection.this[string]" )]
		protected Option GetOptionForName( string option )
		{
			if( option == null )
				throw new ArgumentNullException( "option" );
			try
			{
				return base[option];
			}
			catch( KeyNotFoundException )
			{
				return null;
			}
		}

		protected override void InsertItem( int index, Option item )
		{
			base.InsertItem( index, item );
			AddImpl( item );
		}

		protected override void RemoveItem( int index )
		{
			Option p = Items[index];
			base.RemoveItem( index );
			// KeyedCollection.RemoveItem() handles the 0th item
			for( int i = 1; i < p.Names.Length; ++i )
			{
				Dictionary.Remove( p.Names[i] );
			}
		}

		protected override void SetItem( int index, Option item )
		{
			base.SetItem( index, item );
			AddImpl( item );
		}

		private void AddImpl( Option option )
		{
			if( option == null )
				throw new ArgumentNullException( "option" );
			List<string> added = new List<string>( option.Names.Length );
			try
			{
				// KeyedCollection.InsertItem/SetItem handle the 0th name.
				for( int i = 1; i < option.Names.Length; ++i )
				{
					Dictionary.Add( option.Names[i], option );
					added.Add( option.Names[i] );
				}
			}
			catch( Exception )
			{
				foreach( string name in added )
					Dictionary.Remove( name );
				throw;
			}
		}

		public OptionSet Add( string header )
		{
			if( header == null )
				throw new ArgumentNullException( "header" );
			Add( new Category( header ) );
			return this;
		}

		internal sealed class Category: Option
		{

			// Prototype starts with '=' because this is an invalid prototype
			// (see Option.ParsePrototype(), and thus it'll prevent Category
			// instances from being accidentally used as normal options.
			public Category( string description )
				: base( "=:Category:= " + description, description )
			{
			}

			protected override void OnParseComplete( OptionContext c )
			{
				throw new NotSupportedException( "Category.OnParseComplete should not be invoked." );
			}
		}


		public new OptionSet Add( Option option )
		{
			base.Add( option );
			return this;
		}

		sealed class ActionOption: Option
		{
			Action<OptionValueCollection> action;

			public ActionOption( string prototype, string description, int count, Action<OptionValueCollection> action )
				: base( prototype, description, count )
			{
				if( action == null )
					throw new ArgumentNullException( "action" );
				this.action = action;
			}

			protected override void OnParseComplete( OptionContext c )
			{
				action( c.OptionValues );
			}
		}

		public OptionSet Add( string prototype, Action<string> action )
		{
			return Add( prototype, null, action );
		}

		public OptionSet Add( string prototype, string description, Action<string> action )
		{
			if( action == null )
				throw new ArgumentNullException( "action" );
			Option p = new ActionOption( prototype, description, 1,
					delegate( OptionValueCollection v ) { action( v[0] ); } );
			base.Add( p );
			return this;
		}

		public OptionSet Add( string prototype, OptionAction<string, string> action )
		{
			return Add( prototype, null, action );
		}

		public OptionSet Add( string prototype, string description, OptionAction<string, string> action )
		{
			if( action == null )
				throw new ArgumentNullException( "action" );
			Option p = new ActionOption( prototype, description, 2,
					delegate( OptionValueCollection v ) { action( v[0], v[1] ); } );
			base.Add( p );
			return this;
		}

		sealed class ActionOption<T>: Option
		{
			Action<T> action;

			public ActionOption( string prototype, string description, Action<T> action )
				: base( prototype, description, 1 )
			{
				if( action == null )
					throw new ArgumentNullException( "action" );
				this.action = action;
			}

			protected override void OnParseComplete( OptionContext c )
			{
				action( Parse<T>( c.OptionValues[0], c ) );
			}
		}

		sealed class ActionOption<TKey, TValue>: Option
		{
			OptionAction<TKey, TValue> action;

			public ActionOption( string prototype, string description, OptionAction<TKey, TValue> action )
				: base( prototype, description, 2 )
			{
				if( action == null )
					throw new ArgumentNullException( "action" );
				this.action = action;
			}

			protected override void OnParseComplete( OptionContext c )
			{
				action(
						Parse<TKey>( c.OptionValues[0], c ),
						Parse<TValue>( c.OptionValues[1], c ) );
			}
		}

		public OptionSet Add<T>( string prototype, Action<T> action )
		{
			return Add( prototype, null, action );
		}

		public OptionSet Add<T>( string prototype, string description, Action<T> action )
		{
			return Add( new ActionOption<T>( prototype, description, action ) );
		}

		public OptionSet Add<TKey, TValue>( string prototype, OptionAction<TKey, TValue> action )
		{
			return Add( prototype, null, action );
		}

		public OptionSet Add<TKey, TValue>( string prototype, string description, OptionAction<TKey, TValue> action )
		{
			return Add( new ActionOption<TKey, TValue>( prototype, description, action ) );
		}

		public OptionSet Add( ArgumentSource source )
		{
			if( source == null )
				throw new ArgumentNullException( "source" );
			sources.Add( source );
			return this;
		}

		protected virtual OptionContext CreateOptionContext()
		{
			return new OptionContext( this );
		}

		public List<string> Parse( IEnumerable<string> arguments )
		{
			if( arguments == null )
				throw new ArgumentNullException( "arguments" );
			OptionContext c = CreateOptionContext();
			c.OptionIndex = -1;
			bool process = true;
			List<string> unprocessed = new List<string>();
			Option def = Contains( "<>" ) ? this["<>"] : null;
			ArgumentEnumerator ae = new ArgumentEnumerator( arguments );
			foreach( string argument in ae )
			{
				++c.OptionIndex;
				if( argument == "--" )
				{
					process = false;
					continue;
				}
				if( !process )
				{
					Unprocessed( unprocessed, def, c, argument );
					continue;
				}
				if( AddSource( ae, argument ) )
					continue;
				if( !Parse( argument, c ) )
					Unprocessed( unprocessed, def, c, argument );
			}
			if( c.Option != null )
				c.Option.Invoke( c );
			return unprocessed;
		}

		class ArgumentEnumerator: IEnumerable<string>
		{
			List<IEnumerator<string>> sources = new List<IEnumerator<string>>();

			public ArgumentEnumerator( IEnumerable<string> arguments )
			{
				sources.Add( arguments.GetEnumerator() );
			}

			public void Add( IEnumerable<string> arguments )
			{
				sources.Add( arguments.GetEnumerator() );
			}

			public IEnumerator<string> GetEnumerator()
			{
				do
				{
					IEnumerator<string> c = sources[sources.Count - 1];
					if( c.MoveNext() )
						yield return c.Current;
					else
					{
						c.Dispose();
						sources.RemoveAt( sources.Count - 1 );
					}
				} while( sources.Count > 0 );
			}

			IEnumerator IEnumerable.GetEnumerator()
			{
				return GetEnumerator();
			}
		}

		bool AddSource( ArgumentEnumerator ae, string argument )
		{
			foreach( ArgumentSource source in sources )
			{
				IEnumerable<string> replacement;
				if( !source.GetArguments( argument, out replacement ) )
					continue;
				ae.Add( replacement );
				return true;
			}
			return false;
		}

		private static bool Unprocessed( ICollection<string> extra, Option def, OptionContext c, string argument )
		{
			if( def == null )
			{
				extra.Add( argument );
				return false;
			}
			c.OptionValues.Add( argument );
			c.Option = def;
			c.Option.Invoke( c );
			return false;
		}

		private readonly Regex ValueOption = new Regex(
			@"^(?<flag>--|-|/)(?<name>[^:=]+)((?<sep>[:=])(?<value>.*))?$" );

		protected bool GetOptionParts( string argument, out string flag, out string name, out string sep, out string value )
		{
			if( argument == null )
				throw new ArgumentNullException( "argument" );

			flag = name = sep = value = null;
			Match m = ValueOption.Match( argument );
			if( !m.Success )
			{
				return false;
			}
			flag = m.Groups["flag"].Value;
			name = m.Groups["name"].Value;
			if( m.Groups["sep"].Success && m.Groups["value"].Success )
			{
				sep = m.Groups["sep"].Value;
				value = m.Groups["value"].Value;
			}
			return true;
		}

		protected virtual bool Parse( string argument, OptionContext c )
		{
			if( c.Option != null )
			{
				ParseValue( argument, c );
				return true;
			}

			string f, n, s, v;
			if( !GetOptionParts( argument, out f, out n, out s, out v ) )
				return false;

			Option p;
			if( Contains( n ) )
			{
				p = this[n];
				c.OptionName = f + n;
				c.Option = p;
				switch( p.OptionValueType )
				{
				case OptionValueType.None:
					c.OptionValues.Add( n );
					c.Option.Invoke( c );
					break;
				case OptionValueType.Optional:
				case OptionValueType.Required:
					ParseValue( v, c );
					break;
				}
				return true;
			}
			// no match; is it a bool option?
			if( ParseBool( argument, n, c ) )
				return true;
			// is it a bundled option?
			if( ParseBundledValue( f, string.Concat( n + s + v ), c ) )
				return true;

			return false;
		}

		private void ParseValue( string option, OptionContext c )
		{
			if( option != null )
				foreach( string o in c.Option.ValueSeparators != null
						? option.Split( c.Option.ValueSeparators, c.Option.MaxValueCount - c.OptionValues.Count, StringSplitOptions.None )
						: new string[] { option } )
				{
					c.OptionValues.Add( o );
				}
			if( c.OptionValues.Count == c.Option.MaxValueCount ||
					c.Option.OptionValueType == OptionValueType.Optional )
				c.Option.Invoke( c );
			else if( c.OptionValues.Count > c.Option.MaxValueCount )
			{
				throw new OptionException( localizer( string.Format(
								"Error: Found {0} option values when expecting {1}.",
								c.OptionValues.Count, c.Option.MaxValueCount ) ),
						c.OptionName );
			}
		}

		private bool ParseBool( string option, string n, OptionContext c )
		{
			Option p;
			string rn;
			if( n.Length >= 1 && ( n[n.Length - 1] == '+' || n[n.Length - 1] == '-' ) &&
					Contains( ( rn = n.Substring( 0, n.Length - 1 ) ) ) )
			{
				p = this[rn];
				string v = n[n.Length - 1] == '+' ? option : null;
				c.OptionName = option;
				c.Option = p;
				c.OptionValues.Add( v );
				p.Invoke( c );
				return true;
			}
			return false;
		}

		private bool ParseBundledValue( string f, string n, OptionContext c )
		{
			if( f != "-" )
				return false;
			for( int i = 0; i < n.Length; ++i )
			{
				Option p;
				string opt = f + n[i].ToString();
				string rn = n[i].ToString();
				if( !Contains( rn ) )
				{
					if( i == 0 )
						return false;
					throw new OptionException( string.Format( localizer(
									"Cannot bundle unregistered option '{0}'." ), opt ), opt );
				}
				p = this[rn];
				switch( p.OptionValueType )
				{
				case OptionValueType.None:
					Invoke( c, opt, n, p );
					break;
				case OptionValueType.Optional:
				case OptionValueType.Required:
					{
						string v = n.Substring( i + 1 );
						c.Option = p;
						c.OptionName = opt;
						ParseValue( v.Length != 0 ? v : null, c );
						return true;
					}
				default:
					throw new InvalidOperationException( "Unknown OptionValueType: " + p.OptionValueType );
				}
			}
			return true;
		}

		private static void Invoke( OptionContext c, string name, string value, Option option )
		{
			c.OptionName = name;
			c.Option = option;
			c.OptionValues.Add( value );
			option.Invoke( c );
		}

		private const int OptionWidth = 29;
		private const int Description_FirstWidth = 80 - OptionWidth;
		private const int Description_RemWidth = 80 - OptionWidth - 2;

		public void WriteOptionDescriptions( TextWriter o )
		{
			foreach( Option p in this )
			{
				int written = 0;

				Category c = p as Category;
				if( c != null )
				{
					WriteDescription( o, p.Description, "", 80, 80 );
					continue;
				}

				if( !WriteOptionPrototype( o, p, ref written ) )
					continue;

				if( written < OptionWidth )
					o.Write( new string( ' ', OptionWidth - written ) );
				else
				{
					o.WriteLine();
					o.Write( new string( ' ', OptionWidth ) );
				}

				WriteDescription( o, p.Description, new string( ' ', OptionWidth + 2 ),
						Description_FirstWidth, Description_RemWidth );
			}

			foreach( ArgumentSource s in sources )
			{
				string[] names = s.GetNames();
				if( names == null || names.Length == 0 )
					continue;

				int written = 0;

				Write( o, ref written, "  " );
				Write( o, ref written, names[0] );
				for( int i = 1; i < names.Length; ++i )
				{
					Write( o, ref written, ", " );
					Write( o, ref written, names[i] );
				}

				if( written < OptionWidth )
					o.Write( new string( ' ', OptionWidth - written ) );
				else
				{
					o.WriteLine();
					o.Write( new string( ' ', OptionWidth ) );
				}

				WriteDescription( o, s.Description, new string( ' ', OptionWidth + 2 ),
						Description_FirstWidth, Description_RemWidth );
			}
		}

		void WriteDescription( TextWriter o, string value, string prefix, int firstWidth, int remWidth )
		{
			bool indent = false;
			foreach( string line in GetLines( localizer( GetDescription( value ) ), firstWidth, remWidth ) )
			{
				if( indent )
					o.Write( prefix );
				o.WriteLine( line );
				indent = true;
			}
		}

		bool WriteOptionPrototype( TextWriter o, Option p, ref int written )
		{
			string[] names = p.Names;

			int i = GetNextOptionIndex( names, 0 );
			if( i == names.Length )
				return false;

			if( names[i].Length == 1 )
			{
				Write( o, ref written, "  -" );
				Write( o, ref written, names[0] );
			}
			else
			{
				Write( o, ref written, "      --" );
				Write( o, ref written, names[0] );
			}

			for( i = GetNextOptionIndex( names, i + 1 );
					i < names.Length; i = GetNextOptionIndex( names, i + 1 ) )
			{
				Write( o, ref written, ", " );
				Write( o, ref written, names[i].Length == 1 ? "-" : "--" );
				Write( o, ref written, names[i] );
			}

			if( p.OptionValueType == OptionValueType.Optional ||
					p.OptionValueType == OptionValueType.Required )
			{
				if( p.OptionValueType == OptionValueType.Optional )
				{
					Write( o, ref written, localizer( "[" ) );
				}
				Write( o, ref written, localizer( "=" + GetArgumentName( 0, p.MaxValueCount, p.Description ) ) );
				string sep = p.ValueSeparators != null && p.ValueSeparators.Length > 0
					? p.ValueSeparators[0]
					: " ";
				for( int c = 1; c < p.MaxValueCount; ++c )
				{
					Write( o, ref written, localizer( sep + GetArgumentName( c, p.MaxValueCount, p.Description ) ) );
				}
				if( p.OptionValueType == OptionValueType.Optional )
				{
					Write( o, ref written, localizer( "]" ) );
				}
			}
			return true;
		}

		static int GetNextOptionIndex( string[] names, int i )
		{
			while( i < names.Length && names[i] == "<>" )
			{
				++i;
			}
			return i;
		}

		static void Write( TextWriter o, ref int n, string s )
		{
			n += s.Length;
			o.Write( s );
		}

		private static string GetArgumentName( int index, int maxIndex, string description )
		{
			if( description == null )
				return maxIndex == 1 ? "VALUE" : "VALUE" + ( index + 1 );
			string[] nameStart;
			if( maxIndex == 1 )
				nameStart = new string[] { "{0:", "{" };
			else
				nameStart = new string[] { "{" + index + ":" };
			for( int i = 0; i < nameStart.Length; ++i )
			{
				int start, j = 0;
				do
				{
					start = description.IndexOf( nameStart[i], j );
				} while( start >= 0 && j != 0 ? description[j++ - 1] == '{' : false );
				if( start == -1 )
					continue;
				int end = description.IndexOf( "}", start );
				if( end == -1 )
					continue;
				return description.Substring( start + nameStart[i].Length, end - start - nameStart[i].Length );
			}
			return maxIndex == 1 ? "VALUE" : "VALUE" + ( index + 1 );
		}

		private static string GetDescription( string description )
		{
			if( description == null )
				return string.Empty;
			StringBuilder sb = new StringBuilder( description.Length );
			int start = -1;
			for( int i = 0; i < description.Length; ++i )
			{
				switch( description[i] )
				{
				case '{':
					if( i == start )
					{
						sb.Append( '{' );
						start = -1;
					}
					else if( start < 0 )
						start = i + 1;
					break;
				case '}':
					if( start < 0 )
					{
						if( ( i + 1 ) == description.Length || description[i + 1] != '}' )
							throw new InvalidOperationException( "Invalid option description: " + description );
						++i;
						sb.Append( "}" );
					}
					else
					{
						sb.Append( description.Substring( start, i - start ) );
						start = -1;
					}
					break;
				case ':':
					if( start < 0 )
						goto default;
					start = i + 1;
					break;
				default:
					if( start < 0 )
						sb.Append( description[i] );
					break;
				}
			}
			return sb.ToString();
		}

		private static IEnumerable<string> GetLines( string description, int firstWidth, int remWidth )
		{
			return StringCoda.WrappedLines( description, firstWidth, remWidth );
		}
	}
}
